I found the article interesting as well and very easy to understand. It seems to me that the Biewer standard still has significant coloring on the back & head, which would suggest the mix with one other breed. I wonder whether it could be determined which one is the culprit?
I know that Mr. Biewer had other breed dogs. Could DNA determine which breed supplied pie-bald gene?
I have seen all white & other lighter colored partis - which I guess would mean a mix with more than one breed.
There are really good & ethical breeders out there. There are also the GREEDERS, however, who breed everything under the sun. I can see very easily how other breeds could be mixed in - even on purpose - to obtain a desired look.
Thanks again. Keep the information coming!
Tracey